Question

How do you solve `4cosx=2cosx+1`?

Answer 1

`x=2npi+-pi/3`, where `n` is an integer.

Explanation:

`4cosx=2cosx+1`

`hArr4cosx-2cosx=1`

or `2cosx=1`

or `cosx=1/2=cos(pi/3)` or `cos(-pi/3)`,

as `cos(-A)=cosA`

Further cosine function has a periodicity of `2pi`,

Hence `x=2npi+-pi/3`, where `n` is an integer.